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Chapter 10: Nematodes

Abstract

Nematodes may play a major role in limiting persistence and production of tall fescue [Lolium arundinaceum (Schreb.) Darbysh.] in the southeastern United States. These parasites tend to cause greater plant damage in sandy soils than in soils of heavier texture because light-textured soils are conducive to nematode activity and to drought stress. The lance nematode (Hoplolaimus spp.), the stubby-root nematode [Paratrichodorus minor (Colbran)], the pin nematode (Paratylenchus spp.), and the lesion nematode [Pratylenchus scribneri (Steiner)] all have been shown to damage tall fescue in either greenhouse pots or field plots. The symbiotic endophyte of tall fescue, Neotyphodium coenophialum (Morgan-Jones and Gams) Glenn, Bacon, and Hanlin, confers resistance to some but not to all plant-parasitic nematodes. The mechanism by which the endophyte confers resistance to nematodes in tall fescue is not known. The endophyte is not present in the roots; therefore, the fungus either induces physiological changes in the plant or produces toxins and repellents that are translocated to the roots.